Application Of Refractory Raw Material Mullite

Application of refractory raw material mullite
Mullite is an excellent refractory material. In addition, mullite is also a high-temperature structural material, which is widely used in other industries.
(1) Mullite refractory material
Mullite, as a refractory material with excellent properties, boasts a high melting point, strong high-temperature strength, low thermal expansion coefficient, and superior thermal shock resistance, making it a refractory material in many industrial fields. As an aggregate, mullite is widely used in metallurgy, glass, ceramics, and other fields. In the metallurgical industry, mullite can be used for hot blast stove bricks or kiln furniture bricks; in the glass industry, mullite can be used in glass containers, water feeders, and the top structures of glass chambers; in the ceramic field, mullite can be used for high-temperature structural ceramics; in the gas industry, mullite can be used in oil and gasification equipment, as well as in all gasification workshop coke ovens and gas generators. Mullite bricks can serve as the main component of the upper lining of melting furnaces, blast furnaces, and continuous casting furnaces. In Japan, pads made from slag are applied to the lining of kilns. These ZrO2/AL2O3/mullite slag bricks contain 3-6 wt% ZrO2 and less than 20 wt% SiO2, and exhibit excellent corrosion resistance and thermal shock resistance.
(2) Mullite coating
Many ceramic and metallic materials can suffer damage when exposed to high temperatures, reductions, oxidations, and other environments for extended periods. This issue can be addressed by coating the material surface with a compound coating material that remains stable in the usage environment. Mullite's chemical stability, good corrosion resistance, and excellent performance make it widely used in composite coatings.
(3) Mullite composite material
Mullite is widely used in high-temperature thermal materials due to its excellent high-temperature mechanical properties, chemical stability, creep resistance, thermal shock resistance, and low thermal expansion coefficient. However, mullite lacks a dislocation slip system, and when the external load exceeds a certain limit, internal microcracks will form to consume energy, leading to catastrophic failure of mullite ceramics. Therefore, how to toughen mullite materials has become a research hotspot in recent years. Researchers both domestically and internationally have conducted extensive studies on mullite composites and have achieved certain results in the field of mullite toughening. Mullite composites include mullite matrices, mullite fibers, etc. Mullite composites can reduce the inherent brittleness of the mullite material system and enhance its strength and toughness. After years of effort, the thermodynamic behavior of mullite-based multiphase materials has been improved through particle reinforcement (SiC, ZrO2) or flake reinforcement, and certain progress has been made in mullite toughening.